Exothermic lined feed-head frame



Jan. 28, 1953 H. NOUVEAU EXOTHERMIC LINED FEED-HEAD FRAME 2 Sheets-Sheet1 Filed May 16, 1955 Jan. 28, 1958 H. NOUVEAU EXOTHERMIC LINED FEED-HEADFRAME Filed May 16, 1955 2 Sheets-Sheet 2 Fig. 3

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United States Patent fifice EXOTHERMIC LINED FEED-HEAD FRAME HenriNouveau, Saint-Germain les Corbeil, France, as-

signor to S. A. R. L. Doittau Produits Metallurgie, Seine-et-Oise,France, a corporation of France Application May 16, 1955, Serial No.508,658 Claims priority, application France October 11, 1954 2 Claims.(Cl. 22-147) This invention relates to the casting of cast parts.

It is known that in the casting of cast parts and more particularly tometal ingots, it is necessary to maintain the head of the ingot orfeed-head in a molten condition so that the molten metal will feed thebody of the part or ingot as the latter shrinks during solidification.

In order to effect this prolongation of the liquid state in the head ofthe ingot or feed-head, use is made either of insulating and refractorylinings or of exothermic linings.

The first prevent loss of heat and the second, by their combustion,constitute a source of heat which is supplied to the metal.

My U. S. co-pending specification No. 404,928 of January 19, 1954describes a method which is concerned essentially with agglomerableexothermic materials and consists in using the exothermic material inthe form of a lining of the wall of the feed-head frame or of the upperportion of the ingot mold, leaving an air gap between at least one partof the exothermic lining and the wall.

This air gap acts as a heat insulation and prevents the considerablelosses of heat which would otherwise be produced by conductibilitybetween rthe contacting.

parts of the exothermic product and the ingot mold.

It has now been found according to this invention that the exothermiclining used in this manner often burns only over a part of itsthickness. Moreover, the burned layer in contact with the metal has astronginsulating effeet so that the heat tends to be diffused towardsthe outside. These two factors result in the thickness of the liningbeing increased beyond What would be strictly necessary for supplyingthe feed-head with the heat required to maintain the metal in the moltencondition during a given time. The result is a considerable loss ofexpensive exothermic products.

The present invention has as its object to overcome these disadvantagesand provides a method of using exothermic materials of the typeconsisting in using the exothermic material in the form of a lining forthe wall of the feed-head frame or of the ingot mold in such an man-.

ner as to bring the lining into contact with the molten metalconstituting the feed-head, the method being characterized in thatbetween :the exothermic lining and the said wall there is interposed alayer of a solid insulating material.

With this method the inner part of the lining of exo thermic materialburns upon contact with the molten metal and passes its heat into themetal. The outer part prevents the heat from being diffused towards theoutside.

The insulating layer is preferably constructed of an insulating andrefractory material which is either naturally or artificially porous soas to allow the diffusion of the combustion gases or occluded gases.

It has further been found that with the aforesaid method, the metalpasses downwards in a very uniform manner, with the upper surfaceremaining plane, and that it was possible to reduce the height of theexothermic lining substantially to the zone in which the surface of thecording to a preferred embodiment of the invention the .lining isconstituted by an insulating lining extending chamotte, and kiese-lguhr.

between the maximum high point and the maximum low point of the surfaceof the metal in the ingot mould, and an inner lining of exothermicmaterial.

This improvement has several advantages. Not only does it allow thequantity of exothermic material used to be reduced, but also the stateof the surface ofthe part of the feed-head situated below .theexothermic lining is very much improved since it is similar to that ofan ingot cast in a sand mould. It therefore provides a better yield ofmarketable products.

The method according to the present invention is preferably combinedwith the method which is the subject of my said co-pending specificationSer. No. 404,928, i. e. an air gap is provided between at least one partof the rear face of the insulating layer and the wall of the ingotmould, which not only has the result of improving the heat insulation ofthe feed-head but also ensures the circulation of the combustion gasesand of the occluded gases which have passed through the insulating wall.However, since the insulating function of this air gap is thus madesecondary, it is possible to reduce its size. If desired, collectingchannels can be formed in the mass of the insulating layer itself at thejunction of the exothermic and insulating layers or in the exothermiclayer.

Finally, it may be advantageous for certain applications to combinechannels situated on the outer face of the insulating layer and on theinner face thereof and/or in the mass of the exothermic materials. Thesechannels collect the combustion gases. Now it has been found that thiscombustion is incomplete and these gases have a.

considerable latent heat energy which is liberated when they arrive inan oxygenated zone, i. e. when they issue from the channels. inaccordance with the invention and more especially when the lining ofexothermic materials is limited to the zone comprised substantiallybetween :the upper level of the molten metal and the lower level reachedafter shrinkage and solidification, collecting channels are providedbetween the rear face of the exothermic lining and the insulatinglining, the said channels opening at :the upper part of the exothermiclining towards the interior of the ingot mold. The heat give off by thecombustion of these gases within the feed-head frame limits the surfaceheat loss and makes it possible to reduce the facing of exothermicmaterials, it being possible to enrich :the said facing withoxygen-generating products in order to ensure the combustion of the saidgases. In this case, it is advantageous to choose an insulating layerimpermeable to gases or to render it impermeable by a coating such asthe adhesive connecting the exothermic slab and the insulating lining.

The relative thicknesses of :the two layers can vary. They arepreferably chosen so as to substitute, for the part of the layer ofexothermic material whose heat resulting from combustion is not entirelyused in carrying into effect the method according to my said co-pendingspecification Ser. No. 404,928, a layer of insulating material of atleast equal thickness. This thickness varies in practice between thethickness and half of the thickness of the exothermic layer necessaryfor ensuring the 'supply of heat necessary for maintaining the ingothead in a molten condition.

The insulating layer can be constructed of any insulating material, andmore especially of agglomerated siliceous sand, of refractory materialsuch as agglomerated silica,

not naturally porous, for example a layer of chamotte, perforations canbe formed therein if necessary.

The lining can be formed in one piece and constructed Patented Jan. 28,1958 When the insulating layer is mold by applying a layer of insulatingmaterial and then a layer of exothermic mixture but it is preferablyformed of a plurality of prefabricated elements assembled in thefeed-head frame. othermic part can be molded and baked independently andlater connected, more especially by gluing, before or during positioningin the feed-head frame. However, it is preferable to construct the twoparts in the form of a cast element in one piece, in which case therefractory product is placed first of all in the bottom of the mold andthen the assembly is conveyed to a drying or baking furnace.

If the cross-section of the feed-head is angular, the faces of thelining are preferably connected by a wide curve, since a sharp angleencourages the solidification of the edges and prevents the metal frommoving downwards over the entire periphery. The curve is preferablyformed of the insulating material, which makes it possible Theinsulating part and the exto give the layer of exothermic material auniform thickness.

The present invention also includes as novel industrial products, theprefabricated slabs which are to form the linings, the slabs comprisinga layer of insulating material lined with a layer of exothermic materialand more especially such slabs wherein the lining of exothermic materialis limited to a part of the height of the slab.

One constructional example of the equipment for carrying into effect themethod according to the invention will now be described with referenceto the accompanying drawings, in which:

Fig. 1 is a sectional view taken on the line II of Fig. 2 of thefeed-head frame with its lining according to a first embodiment;

Fig. 1a is a corresponding sectional view of the feedhead frame withpartial lining according to a second embodiment;

Fig. 2 is a half-section taken on the line II-II of Fig. 1;

Fig. 2a is a half-section taken on the line II-II of Fig. 1a;

Fig. 3 is a vertical sectional view of the feed-head frame with itslining according to a third embodiment;

Fig. 4 is a half-section corresponding to Fig. 2 of a constructionalvariant;

Fig. 5 is a sectional view of the feed-head frame with partial liningaccording to a fourth embodiment, and

Fig. 6 is a partial front elevation of the exothermic lining asconstructed according to Fig. 5.

Referring to the drawings, the feed-head frame 1 is mounted on an ingotmold 2. The feed-head frame is of square section and constitutes atruncated pyramid.

The feed-head frame 1 bears against the upper edge of the ingot mold 2with a base portion 3 which, in Figs. 1 and la projects inwards five toten millimetres so as to form a continuous projecting band 4 over theentire periphery of the base portion. Bands 5 which, relatively to theinternal surface of the feed-head frame, have the same extra thicknessas the band 4 and are arranged perpendicularly to the latter, are formedon the inner faces of the feed-head frame. The upper edge of the saidframe is formed with an inwardly projecting portion 6 which limits theuseful aperture of the feed-head frame.

The method according to the invention is carried into effect by the useof a lining constituted by four trapezoidal slabs. In Fig. 1 the slabsare formed of a layer of insulating, refractory and porous material 7and a layer of exothermic material 8 in contact with the molten metal.The lateral edges 9 of the slabs thus constructed are bevelled at 45 soas to allow them to be assembled in the frame and they are so fashionedas to form a pronounced curve at the point of junction between twoslabs. The lower edge 10 is likewise bevelled.

In Fig. 1a the exothermic lining 11 is substantially limited to-the zonecomprised between the maximum high point16 and the maximum low point 17of the metal in theingot mold. These two types of slab can be formed bymolding. in the form of. an element made in one piece, or can be formedof two separate 'rnolded elements joined together by an adhesive.

In Figs. 1, la, 2 and 2a, the slabs are fitted inside the feed-headframe with interposition, betweentheir external faces and the bearingsurfaces of the bands 4 and 5, of a layer of refractory adhesive. Afterpositioning, the slabs constituting the lining leave between themselves,the internal wall of the feed-head frame 1 and the bands 4 or 5 formingribs, an air gap 13 which is from five to ten millimetres thick,depending upon the amount of projection of the ribs, and the said airgap constitutes a supplementary heat-insulating means. Formed betweenthe upper edge of the slabs and the inwardly projecting rim 6 is a gapthrough whichbccluded gases diffused through the slabs can be evacuated.

In Fig. 3 the slabs are constructed in the mold by the application of alayer ofinsulating material 7 anda layer of exothermic material 8. Thisform of embodiment is similar, apart from the method of manufacture, tothat described with reference to Figs. 1 and 2. In the form ofembodiment which is the subject of Fig. 4, collecting channels 14 areformed in the insulating material and at the junction of the exothermicand insulating layers for the evacuation of occluded gases at the upperpart of the ingot mold. These channels 14 make it possible to dispensewith the air gap 13 of Figs. 1 and la, whose insulating function wassecondary.

In Figs. 5 and 6 the exothermic lining 15 is, as in Figs. 7

1a and 2a, limited to the zone comprised substantially between the upperlevel 16 of the molten metal and the lower level 17 reached aftershrinkage and solidification,

and is fitted into and connected by adhesive to the insulating lining 18to form the lining slab.

The combustion gases of the exothermic lining 15, issue chiefly towardsthe rear face by reason of the properties of the already burned mass ofthe lining; the said gases are evacuated through channels 19 formedbetween the rear face of the exothermic lining 15 and the insulatinglining 18. These channels 19 open at the upper portion of the exothermiclining 15 towards the interior of the ingot mold and the gases areburned at 20 within the feedhead frame.

It will be understood that if the forms of embodiment hereinbeforedescribed relate more especially to the casting of ingots, the inventionis also applicable, under the same conditions, to the production of castparts.

What I claim is:

1. In a feed head metal casing for an ingot mold which casing isprovided with an inner lining comprising a layer of insulating materialand a layer of exothermic material that is exposed to molten metal of afeed head, the said metallic feed head casing being imperforate andhaving an inwardly projecting lower rim and inwardly projecting, spacednarrow ribs extending upwardly from said rim, said rim and ribs havingcemented on the inwardly directed surface thereof, the external face ofpreformed blocks comprising a layer of agglomerated material forming agas-pervious insulating layer and an internal layer of exothermicmaterial, so as to allow the gases to freely escape during a castingoperation through the insulating layer and upwardly extending passagesbetween said blocks, ribs and feed head casing.

2. In a feed head metal casing for an ingot mold which casing isprovided with an inner lining comprising a layer of insulating materialand a layer of exothermic material that is exposed to molten metal of afeed head, the said metallicfeed head casing being .imperforate andhaving an inwardly projecting lower rim and inwardly projecting,

spaced narrow ribs extending upwardly from said rim, said rim and ribshaving cemented on the inwardly directed. surface thereof, the externalface of preformed bloclrs comprising a layer of agglomerated materialforming a gas pervious insulating layer and in recesses provided in theinternal face of said blocks on a part of their height a layer ofexothermic material, so as to allow the gases to freely escape during acasting operation through the insulating layer and upwardly extendingpassages between said blocks, ribs and feed head casing.

References Cited in the file of this patent UNITED STATES PATENTS1,717,575 Messier June 18, 1929 6 Coxey Dec. 31, 1939 Charman et a1.Dec. 11, 1945 Peterson May 18, 1954 FOREIGN PATENTS Great Britain Aug.6, 1940 Switzerland Sept. 22, 1953

